port(m1): wave 7h — Unity overloads + SDK return types + RoomRoot:UIBase (56->40)

- Resources.LoadAsync(string) non-generic, LayerMask implicit-from-int, Animation
  string indexer.
- SDK return-type fixes: RedShellSDK.MarkConversion/LogEvent return IEnumerator
  (StartCoroutine arg), Packsize.Test() returns bool (!Test()).
- RoomRoot : UIBase (decomp base) so TopBar/Footer's (RoomRoot) casts succeed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SVSim.BattleEngine/Shim/GodObjects/ClosureStubs.cs

@@ -21,7 +21,7 @@ namespace Wizard.RoomMatch
     public partial class RoomBase { }
     public partial class RoomFormatEventHandler { }
     public partial class RoomWatchEventDispatch { }
-    public partial class RoomRoot { }
+    public partial class RoomRoot : global::UIBase { }
     public partial class RoomConnectChecker { }
     public partial class RoomVisitor { }
     public partial class RoomInviteFriend { }